1 files changed, 51 insertions, 0 deletions
diff --git a/src/drivers/i2c.cpp b/src/drivers/i2c.cpp
new file mode 100644
index 00000000..d3bfaa59
--- /dev/null
+++ b/src/drivers/i2c.cpp
@@ -0,0 +1,51 @@
+#include "i2c.hpp"
+#include <cstdint>
+
+#include "assert.h"
+#include "driver/i2c.h"
+
+namespace gay_ipod {
+
+static constexpr int kCmdLinkSize = I2C_LINK_RECOMMENDED_SIZE(12);
+
+I2CTransaction::I2CTransaction() {
+  // Use a fixed size buffer to avoid many many tiny allocations.
+  buffer_ = (uint8_t*)calloc(sizeof(uint8_t), kCmdLinkSize);
+  handle_ = i2c_cmd_link_create_static(buffer_, kCmdLinkSize);
+  assert(handle_ != NULL && "failed to create command link");
+}
+
+I2CTransaction::~I2CTransaction() {
+  free(buffer_);
+}
+
+esp_err_t I2CTransaction::Execute() {
+  return i2c_master_cmd_begin(I2C_NUM_0, handle_, kI2CTimeout);
+}
+
+I2CTransaction& I2CTransaction::start() {
+  ESP_ERROR_CHECK(i2c_master_start(handle_));
+  return *this;
+}
+
+I2CTransaction& I2CTransaction::stop() {
+  ESP_ERROR_CHECK(i2c_master_stop(handle_));
+  return *this;
+}
+
+I2CTransaction& I2CTransaction::write_addr(uint8_t addr, uint8_t op) {
+  write_ack(addr << 1 | op);
+  return *this;
+}
+
+I2CTransaction& I2CTransaction::write_ack(uint8_t data) {
+  ESP_ERROR_CHECK(i2c_master_write_byte(handle_, data, true));
+  return *this;
+}
+
+I2CTransaction& I2CTransaction::read(uint8_t* dest, i2c_ack_type_t ack) {
+  ESP_ERROR_CHECK(i2c_master_read_byte(handle_, dest, ack));
+  return *this;
+}
+
+}  // namespace gay_ipod